I'd really like to know what ammo you had trouble with. I have not shot mine a lot, and have not bought any specific defensive ammo for carry, but I have not had any feeding issues. Maybe I can buy some different loads than what you have tried (IF I CAN EVEN FIND ANY AMMO, NOW!) and we can compare notes.
I've fed 3 different JHP loads and a bunch of FMJ and never had a hiccup with any... I can't remember specifics on what I used as I'm at work and would have to look at the boxes at the house. Plus my brain does not engage until noon-ish everyday so I'm still in a fog
I know one box was Remington JHP, I do remember that...
Not an LC9, but I run 124gr 9mm +P Speer Gold dots in my Kahr P9. Like others asked, what ammo did you try? I'd question the overall reliability of a gun if it can't run any number of proven JHP rounds. Granted, some guns require a few hundred rounds to break in.